【摘要】：昆蟲能夠將消化吸收的葡萄糖在脂肪體中轉化為海藻糖或作為糖原儲存,當機體需要能量時,海藻糖再轉化為葡萄糖進入糖酵解途徑,己糖激酶(hexokinase,HK)是在此轉化過程合成中間代謝物葡萄糖-6-磷酸的限速酶。為研究柞蠶蛹解除滯育及發(fā)育過程中的糖類代謝規(guī)律,克隆了柞蠶2個己糖激酶同工酶基因,分別命名為Ap HK1和Ap HK2(Gen Bank登錄號:KY624592,KY624593)。2個基因的ORF全長分別為1 455 bp、1 362 bp,編碼484、453個氨基酸。系統(tǒng)進化分析柞蠶HK1和HK2蛋白分布于2個不同的進化分支,不同種類昆蟲的同一類型HK具有更高的同源性。柞蠶5齡幼蟲各組織中,2個HK基因在脂肪體中的表達水平都較高,Ap HK2在各組織中均有表達,分布比Ap HK1更廣,且在中腸、肌肉內也有較高表達。以一化性柞蠶滯育蛹的脂肪體組織為材料,采用qRT-PCR分析長光照(17 h/d)處理解除柞蠶蛹滯育及蛹發(fā)育過程中HK基因的表達規(guī)律,結果表明:2個HK基因的表達量在處理后21 d明顯升高,其中Ap HK2的表達量升高了3.1倍;化蛹后42 d,Ap HK1的表達量升高了2.8倍,而Ap HK2的表達量無顯著變化。同時測定蛹脂肪體中己糖激酶的活性在長光照處理下高于對照組,前期呈現(xiàn)上升趨勢,處理后28 d達到最高值,此后逐漸下降并于處理后35 d趨于穩(wěn)定;測定蛹血淋巴中葡萄糖含量呈先下降后上升的趨勢,這與脂肪體中己糖激酶的活性具有相關性。研究結果顯示柞蠶滯育蛹解除滯育及發(fā)育過程中己糖激酶基因表達上調,在蛹發(fā)育中期己糖激酶酶活力及葡萄糖含量之間呈現(xiàn)出互補關系,即己糖激酶的活性增強,血淋巴中葡萄糖的含量減少。
[Abstract]:Insects can convert digested and absorbed glucose into trehalose in the fat body or store it as a glycogen. When the body needs energy, trehalose is converted into glucose to enter the glycolytic pathway, hexokinase, HK is a rate-limiting enzyme for the synthesis of glucose-6 phosphoric acid, an intermediate metabolite. In order to study the rules of carbohydrate metabolism during deferment and development of tussah silkworm pupae, two isozyme genes of hexokinase were cloned and named Ap HK1 and Ap HK2 (Gen Bank accession number: KY624592,. KY624593). The ORF length of the two genes was 1 455 bp,1 362 bp, encoding 484453 amino acids, respectively. Phylogenetic analysis showed that HK1 and HK2 proteins were distributed in two different branches of evolution, and the homology of the same type of HK in different species of insects was higher. In every tissue of 5th instar larvae of Antheraea pernyi, the expression of two HK genes was higher in fat body, and the expression of Ap HK2 was more extensive than that of Ap HK1 in all tissues, and it was also expressed in midgut and muscle. The fat body tissue of diapause pupae of Antheraea pernyi was used as the material, and the expression of HK gene during diapause and development of tussah silkworm pupae was relieved by qRT-PCR analysis with long illumination (17 h / d). The results showed that the expression of two HK genes increased significantly 21 days after treatment, and the expression of Ap HK2 increased 3.1-fold. At 42 d after pupation, the expression of AP HK1 increased 2.8 times, but the expression of Ap HK2 did not change significantly. At the same time, the activity of hexokinase in fat body of pupae was higher than that of control group under long light treatment. The activity of hexokinase in fat body of pupae increased in early stage, reached the highest value at 28 days after treatment, then decreased gradually and became stable at 35 days after treatment. The content of glucose in hemolymph of pupae decreased first and then increased, which was related to the activity of hexokinase in fat body. The results showed that the expression of hexokinase gene was up-regulated during diapause and development of Antheraea pernyi pupae, and there was a complementary relationship between the activity of hexokinase and the content of glucose, that is, the activity of hexokinase was enhanced. The content of glucose in hemolymph was decreased.
【作者單位】： 沈陽農(nóng)業(yè)大學生物科學技術學院 遼寧省昆蟲資源工程技術研究中心;河南省蠶業(yè)科學研究院;
【基金】：現(xiàn)代農(nóng)業(yè)產(chǎn)業(yè)技術體系建設專項(No.CARS-22) 遼寧省農(nóng)業(yè)領域青年科技創(chuàng)新人才培養(yǎng)計劃項目(No.2014010) 遼寧省教育廳一般項目(No.L2015488)
【分類號】：S885.1
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本文編號：2329084